Report Series: Committee on Astrobiology and Planetary Science Options for the Fifth New Frontiers Announcement of Opportunity (2020) / Chapter Skim
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3 Mission Theme Reconsideration
3 Mission Theme Reconsideration
Pages 15-21
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From page 15... ...
Subsequent sections address each of these mission themes in turn. OCEAN WORLDS Titan Dragonfly is a scientifically and programmatically exciting mission, and it is well-aligned with the overall Ocean Worlds mission theme to "search for the signs of extant life and/or characterize the potential habitability of Titan." Dragonfly very clearly addresses the first of the two science objectives articulated in the NF4 AO (see Box 1.1)
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From page 16... ...
The selection of Dragonfly for Titan under the Ocean Worlds mission theme obviously does not relieve these particular scientific objectives because of the significant differences between the bodies and potential for major scientific advances. Since the NF4 call, scientific discoveries have increased the likelihood that Enceladus's ocean is habitable and have enhanced the position of Enceladus as a high-priority target in the search for life in the solar system.2 Extensive technological development efforts are under way to mature flight instruments for biosignature and life detection on icy bodies and in plumes (see the discussion of ICEE and COLDTech in the "Ocean Worlds" section of Chapter 2)
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From page 17... ...
A future New Frontiers– class mission to the Trojan asteroids could potentially take advantage of technology development, such as advanced solar-electric propulsion, which could permit extended rendezvous at multiple targets, in the manner of the Dawn mission to Vesta and Ceres. However, selecting a Trojan tour mission in NF5 would not be in keeping with the optimum program balance among mission targets and types recommended strongly in V&V.
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From page 18... ...
The proposed IVO payload matches that of the enhanced payload of Io Observer and would perform a similar 10 high-inclination flybys of Io.8 The significant difference between Io Observer and IVO is that the latter is solar powered and proposed on a Discovery budget. The final selections for flight for Discovery 15/16 are anticipated in 2021, prior to the release of the NF5 AO (see Table 1.1)
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From page 19... ...
Finding: Future Juno observations of Io do not warrant reconsideration of inclusion of Io Observer in the NF5 target list by NASA, because of the inherent limitations of the Juno spacecraft with respect to the science objectives of the Io Observer New Frontiers concept. LUNAR GEOPHYSICAL NETWORK The LGN would consist of several identical, long-lived landers distributed across the lunar surface, each carrying instrumentation for geophysical studies.9 The stated primary science objectives are to characterize the Moon's internal structure, seismic activity, global heat flow budget, bulk composition, and magnetic field.
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From page 20... ...
Additional laser ranging nodes would provide substantial scientific return that would complement seismic, magnetic, and heat flow data. Moreover, additional nodes would also yield fundamental astrophysical data that could further test the general theory of relativity, the inverse square law, and the equivalence principle.12 Finding: Scientific discoveries from lunar orbit or in terrestrial laboratories and technical advances in instrumentation since the 2011 decadal survey do not replace or obviate the need for the LGN.
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From page 21... ...
Finding: The scientific rationale in V&V for the LGN has not changed, and if anything has become more compelling, so reconsideration by NASA of inclusion of LGN in the NF5 target list is not warranted. Substantial investment in deployable geophysical instrumentation for the lunar surface over the past decade has made the scientific case for LGN more robust in the sense of being more achievable.
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